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Tosylhydrazone
A tosylhydrazone in organic chemistry is a functional group with the general structure RR'C=N-NH-Ts where Ts is a tosyl group. Organic compounds having this functional group can be accessed by reaction of an aldehyde or ketone with tosylhydrazine. Synthesis As an example ''camphor tosylhydrazone'' is synthesised from camphor and tosylhydrazine in ethanol with hydrochloric acid catalysis. Reactions Hydrolysis is the reverse reaction of formation with regeneration of the carbonyl compound. In the Shapiro reaction tosylhydrazones are used as a leaving group in elimination reactions. This reaction requires a strong base. If sodium methoxide is used as the base the reaction is called a Bamford–Stevens reaction. Tosylhydrazones can be organic reduction, reduced to the corresponding alkanes with reagents such as sodium borohydride and borane. Tosylhydrazone salts can react with metals to form metal carbenes and used in cyclopropanations and epoxidations. An example of a transition me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bamford–Stevens Reaction
The Bamford–Stevens reaction is a chemical reaction whereby treatment of tosylhydrazones with strong base gives alkenes. It is named for the British chemist William Randall Bamford and the Scottish chemist Thomas Stevens Stevens (1900–2000). The usage of aprotic solvents gives predominantly Z-alkenes, while protic solvent gives a mixture of E- and Z-alkenes. As an alkene-generating transformation, the Bamford–Stevens reaction has broad utility in synthetic methodology and complex molecule synthesis. The treatment of tosylhydrazones with alkyl lithium reagents is called the Shapiro reaction. Reaction mechanism The first step of the Bamford–Stevens reaction is the formation of the diazo compound 3. (''also in thCollective Volume (1990) 7:438(PDF)'') In protic solvents, the diazo compound 3 decomposes to the carbenium ion 5. In aprotic solvents, the diazo compound 3 decomposes to the carbene 7. Directed Bamford-Stevens reaction The Bamford–Stevens reaction has n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shapiro Reaction
The Shapiro reaction or tosylhydrazone decomposition is an organic reaction in which a ketone or aldehyde is converted to an alkene through an intermediate hydrazone in the presence of 2 equivalents of organolithium reagent. The reaction was discovered by Robert H. Shapiro in 1967. The Shapiro reaction was used in the Nicolaou Taxol total synthesis. This reaction is very similar to the Bamford–Stevens reaction, which also involves the basic decomposition of tosyl hydrazones. Reaction mechanism In a prelude to the actual Shapiro reaction, a ketone or an aldehyde (1) is reacted with p-toluenesulfonylhydrazide, ''p''-toluenesulfonylhydrazide(2) to form a ''p''-toluenesulfonylhydrazone (or tosylhydrazone) which is a hydrazone (3). Two equivalents of strong base (chemistry), base such as N-Butyllithium, ''n''-butyllithium abstract the Hydron (chemistry), proton from the hydrazone (4) followed by the less carbon acid, acidic proton α to the hydrazone carbon (5), forming a carbanion. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical ( in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (included in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Carbene
A transition metal carbene complex is an organometallic compound featuring a divalent organic ligand. The divalent organic ligand coordinated to the metal center is called a carbene. Carbene complexes for almost all transition metals have been reported. Many methods for synthesizing them and reactions utilizing them have been reported. The term carbene ligand is a formalism since many are not derived from carbenes and almost none exhibit the reactivity characteristic of carbenes. Described often as , they represent a class of organic ligands intermediate between alkyls and carbynes . They feature in some catalytic reactions, especially alkene metathesis, and are of value in the preparation of some fine chemicals. Classification Metal carbene complexes are often classified into two types. The Fischer carbenes named after Ernst Otto Fischer feature strong π-acceptors at the metal and being electrophilic at the carbene carbon atom. Schrock carbenes, named after Richard R. Schrock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylthiocarbamide
Phenylthiocarbamide (PTC), also known as phenylthiourea (PTU), is an organosulfur thiourea containing a phenyl ring. It has the unusual property that it either tastes very bitter or is virtually tasteless, depending on the genetic makeup of the taster. The ability to taste PTC is often treated as a dominant genetic trait, although inheritance and expression of this trait are somewhat more complex. PTC also inhibits melanogenesis and is used to grow transparent fish. About 70% of people can taste PTC, varying from a low of 58% for Indigenous Australians and indigenous peoples of New Guinea to 98% for indigenous peoples of the Americas. One study has found that non-smokers and those not habituated to coffee or tea have a statistically higher percentage of tasting PTC than the general population. PTC does not occur in food, but related chemicals do, and food choice is related to a person's ability to taste PTC. History The tested genetic taste phenomenon of PTC was discovere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Transfer Catalyst
In chemistry, a phase-transfer catalyst or PTC is a catalyst that facilitates the transition of a reactant from one phase into another phase where reaction occurs. Phase-transfer catalysis is a special form of heterogeneous catalysis. Ionic reactants are often soluble in an aqueous phase but insoluble in an organic phase in the absence of the phase-transfer catalyst. The catalyst functions like a detergent for solubilizing the salts into the organic phase. Phase-transfer catalysis refers to the acceleration of the reaction upon the addition of the phase-transfer catalyst. By using a PTC process, one can achieve faster reactions, obtain higher conversions or yields, make fewer byproducts, eliminate the need for expensive or dangerous solvents that will dissolve all the reactants in one phase, eliminate the need for expensive raw materials and/or minimize waste problems. Phase-transfer catalysts are especially useful in green chemistry—by allowing the use of water, the nee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodium Acetate
Rhodium(II) acetate is the coordination compound with the formula Rh2(AcO)4, where AcO− is the acetate ion (). This dark green powder is slightly soluble in polar solvents, including water. It is used as a catalyst for cyclopropanation of alkenes. It is a widely studied example of a transition metal carboxylate complex. Preparation Rhodium(II) acetate is usually prepared by the heating of hydrated rhodium(III) chloride in acetic acid (CH3COOH): Rhodium(II) acetate dimer undergoes ligand exchange, the replacement of the acetate group by other carboxylates and related groups. :Rh2(OAc)4 + 4 HO2CR → Rh2(O2CR)4 + 4 HOAc Structure and properties The structure of rhodium(II) acetate features a pair of rhodium atoms, each with octahedral molecular geometry, defined by four acetate oxygen atoms, water, and a Rh–Rh bond of length 2.39 Å. The water adduct is exchangeable, and a variety of other Lewis bases bind to the axial positions. Copper(II) acetate and chromiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrazone
Hydrazones are a class of organic compounds with the structure . They are related to ketones and aldehydes by the replacement of the oxygen =O with the = functional group. They are formed usually by the action of hydrazine on ketones or aldehydes. Synthesis Hydrazine, organohydrazines, and 1,1-diorganohydrazines react with aldehydes and ketones to give hydrazones. : Phenylhydrazine reacts with reducing sugars to form hydrazones known as osazones, which was developed by German chemist Emil Fischer as a test to differentiate monosaccharides. Uses Hydrazones are the basis for various analyses of ketones and aldehydes. For example, dinitrophenylhydrazine coated onto a silica sorbent is the basis of an adsorption cartridge. The hydrazones are then eluted and analyzed by HPLC using a UV detector. The compound carbonyl cyanide-''p''-trifluoromethoxyphenylhydrazone (abbreviated as FCCP) is used to uncouple ATP synthesis and reduction of oxygen in oxidative phosphorylation in molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-toluenesulfonyl Hydrazide
''p''-Toluenesulfonyl hydrazide is the organic compound with the formula CH3C6H4SO2NHNH2. It is a white solid that is soluble in many organic solvents but not water or alkanes. It is a reagent in organic synthesis. Reactions With ketones and aldehydes, it condenses to give the hydrazones: :CH3C6H4SO2NHNH2 + R2C=O → CH3C6H4SO2NHN=CR2 + H2O Upon heating in solution, it degrades, releasing diimide (N2H2), a useful reducing agent. Triisopropylbenzenesulfonylhydrazide is far more useful for this reaction. Synthesis Toluenesulfonyl hydrazide is prepared by the reaction of a toluenesulfonyl chloride with hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...: :CH3C6H4SO2Cl + 2 NH2NH2 → CH3C6H4SO2NHNH2 + + H2NH3l Reactions : Tosylhydrazides can be installed by nucle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzaldehyde
Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful. It is a colorless liquid with a characteristic almond-like odor. The primary component of bitter almond oil, benzaldehyde can be extracted from a number of other natural sources. Synthetic benzaldehyde is the flavoring agent in imitation almond extract, which is used to flavor cakes and other baked goods. History Benzaldehyde was first extracted in 1803 by the French pharmacist Martrès. His experiments focused on elucidating the nature of amygdalin, the poisonous material found in bitter almonds, the fruit of ''Prunus dulcis''. Further work on the oil by Pierre Robiquet and Antoine Boutron-Charlard, two French chemists, produced benzaldehyde. In 1832, Friedrich Wöhler and Justus von Liebig first synthesized benzaldehyde. Production As of 1999, 7000 tonnes of synthetic and 100 tonnes of natural b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tranylcypromine
Tranylcypromine, sold under the brand name Parnate among others,Drugs.co Page accessed April 17, 2016 is a monoamine oxidase inhibitor (MAOI). More specifically, tranylcypromine acts as nonselective and irreversible inhibitor of the enzyme monoamine oxidase (MAO). It is used as an antidepressant and anxiolytic agent in the clinical treatment of mood and anxiety disorders, respectively. Tranylcypromine is a propylamine formed from the cyclization of amphetamine's side chain; therefore, it is classified as a substituted amphetamine. Medical uses Tranylcypromine is used to treat major depressive disorder, including atypical depression, especially when there is an anxiety component, typically as a second-line treatment.UK Electronic medicines compendiumTranylcypromineLlast updated October 28, 2015 It is also used in depression that is not responsive to reuptake inhibitor antidepressants, such as the SSRIs, TCAs, or bupropion. Systematic reviews and meta-analyses have reported ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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